Finite temperature atomistic‐informed crystal plasticity finite element modeling of single crystal tantalum (α‐Ta) at micron scale

Abstract

AbstractIn this work, we have developed a temperature‐dependent higher‐order Cauchy–Born (THCB) rule for multiscale crystal defect dynamics (MCDD) of crystalline solids based on the harmonic approximation. As a template, we employed the THCB rule to develop an atomistic‐informed constitutive model for the body‐centered cubic (BCC) single crystal tantalum (‐Ta). Considering the effect of strain gradients in different process zone elements, the corresponding higher order stress are used to model crystal plasticity of single crystal ‐Ta. Different from face‐centered cubic crystals, BCC crystals are strongly influenced by temperature. It is shown in this article that the developed finite temperature atomistic‐informed crystal plasticity finite element method is able to capture the temperature‐dependent dislocation substructure and hence crystal plastic deformation. The main contributions and novelties of the present work are highlighted by following findings: (1) A THCB rule and an atomistic‐informed strain gradient theory have been developed, and the corresponding temperature‐related higher‐order stress and elastic tensor formulations are derived; (2) The finite temperature MCDD provides an atomistic‐informed crystal plasticity finite element method that can simulate anisotropic crystal plasticity in any orientation within stereographic triangle at micron scale and above; (3) The developed MCDD is able to capture the non‐Schmid effects of BCC single crystal tantalum (‐Ta); (4) The developed MCDD is able to capture the size effect of single crystal plasticity; and (5) The finite temperature MCDD can simulate the temperature dependent dislocation substructure, and it captures cross‐slip in single crystal tantalum at low temperature (∼20 K) and captures dislocation cell structure at high temperature (∼500 K).